Shares of Affirm Holdings Inc. /zigman2/quotes/223715966/composite AFRM -3.53% are up 4.7% in Wednesday morning trading after the company announced that it will be working with American Airlines Group Inc. /zigman2/quotes/209207041/composite AAL -0.06% to provide buy-now pay-later options for the company's customers. Affirm will be the "exclusive monthly buy now, pay later provider" for aa.com, the American Airlines website, according to a press release. This is the first time that American Airlines has integrated buy-now pay-later options on the aa.com site, Affirm's release said. Customers will be able to use Affirm for airfare costing at least $50 and select from payment options ranging from three to 12 months. Affirm shares have gained 168% over the past three months as the S&P 500 /zigman2/quotes/210599714/realtime SPX +1.32% has risen about 4%.